Metallic soaps of fatty acids and alphahydroxy alkanoic acids



United States Patent lVIETALLIC SOAPS 0F FATTY ACIDS AND ALPHA- HY DROXYALKANOIC A'CIDS Gerald M. Davis, Clark, Arthur L. Fowler, Jr., Metuchen,and Maynard B. Winston, Woodbridge, N. J., assignors to AmericanCyanamid Company, New York, N. Y., a corporation of Maine No Drawing.Application March 29, 1954, Serial No. 419,611

7 Claims. (Cl. 106-243) This invention relates to polyvalent metal soapscapable of forming fluid solutions in organic solvents when dissolvedtherein in amounts up to 30% and to coating, impregnating, sealing andwater-proofing compositions containing them. More particularly, theinvention is directed to mixed polyvalent metal salts wherein both analpha-hydroxy alkanoic acid containing from 8 to 12 carbon atoms and ahigher fatty acid of about to 22 carbon atoms are combined into analuminum, zinc, calcium or magnesium soap composition possessing theproperty of forming low viscosity solutions in volatile hydrocarbon andchlorinated hydrocarbon solvents. The invention includes the soapsthemselves and impregnating and water-proofing compositions containingthem.

The coating and waterproofing properties of the polyvalent metal soaps,better known in the art as metallic soaps, has been well recognized andtheir application of these and similar uses is now firmly established.The most convenient method of applying such polyvalent metal soaps tovarious surfaces such as wood, paper, cloth, leather, masonry,wall-board, and the like, has been to make up a solution thereof in anorganic solvent and to spray the same on the surface to be treated.Various volatile organic solvents have been used in the preparation ofthe polyvalent metal soap solutions, the more common ones including thealiphatic and aromatic hydrocarbons and their halogenated derivatives.

While the foregoing practice has found some success in the art, manydifficulties have been encountered, inasmuch as when more than about 2%or 3% of some soaps are dissolved in some organic solvents, theresulting mass either thickens to such an extent or actually forms asolidified gel, as to render it substantially useless as a sprayablecoating or waterproofing composition. While the thickened mass orsolidified gel can be heated to render it less viscous, the applicationthereof in a heated state is occasionally dangerous due to the volatileand inflammable solvents used and is usually unsatisfactory for mostpurposes. Furthermore, the application of solutions containing only from2% to 3% of the polyvalent metal soap is also highly commercially impractical in view of the low concentration of the solids in thesolution, which factor additionally increases the cost of the productdue to the large amounts of solvent necessary.

Various efforts have been made to solve the foregoing problems byincreasing the soap concentration without undesirably decreasing thefluidity of the resulting solution. Peptizing agents having an acidicnature, such as acetic acid, phenol, tartaric acid, oxalic acid, and thelike, have been used to increase the soap concentration in a solventmixture without affecting the fluidity thereof. This proposal has provento be undesirable commercially in view of the corrosive characterimparted to the composition by such acidic agents. Another elfort hasinvolved the use of the ethanolamines, or the ethanolamine salts of thehigher fatty acids, for the purpose of increasing the concentration ofpolyvalent metal soap 2,793,132 Patented May 21, 1957 solution. Asolutionproduced according to this teaching has not found toowidespreadsuccess.

A principal object of the present invention is to overcome the foregoingdefects and other disadvantages.

Another principal'object of the present invention is to provide animproved, relatively highly concentrated polyvalent metal soap solutionof low viscosity.

A further principal object of the'present invention is to provide animproved coating and waterproofing composition.

A still further principal object of the invention is to provide fluidpolyvalent metal soap solutions containing up to 30% polyvalent metalsoap concentrations.

It has now been found that the foregoing and other objects of thepresent invention may be achieved by the use of an alpha-hydroxyalkanoic acid containing from 8 to 12 carbon atoms, in conjunction withthe fatty acid, or equivalent acid, used in the formation of thepolyvalent metal soap. It has been found that the use of thealpha-hydroxy alkanoic acid remarkably reduces the viscosity of theresulting commercial compositions whereby readily sprayable solutionscontaining high percentages of metallic soaps can be prepared.

Representative alkanoic acids of the present invention would include asillustrative, but not as limitative, the following: alpha-hydroxyoctanoic acid; alpha-hydroxy decanoic acid; alpha-hydroxy dodecanoicacid; 2-hydroxy- 4-methyl-6,6'-dimethyl heptanoic acid;3-ethyl-2-hydroxy heptanoic acid; 6-niethyl-2-hydroxy heptanoic acid;etc. It is to be particularly noted that in all these acids, the hydroxygroup'is 'attacii'ed to the carbon atom adjacent the carboxyl group.

In the preparation of the composition of the invention, any suitablewater-insoluble polyvalent metal soap of a higher fatty acid or'similar' acid'rnay be'e'm'ployed. Examples ar ues soaps include thepolyvalent metal soaps of fatty acidscoirtainin'g'fromfl0 to 22 or morecarbon atoms, su cha's for 'xa'mple, the aluminum, calcium, magnesium,zinc, etc., soapsfof capric, lauric, myristic, palmitic, stearic,ara'chidic, behenic, oleic, palmitoleic, lauroleic, myristoleic,linoleic, ricinoleic, and the like acids?" Mixtures of acids such ashydrogenated fish oil fatty acids, hydrogenated cottonseed oil fattyacids, hydrogenated tallow fatty acids, hydrogenated soya bean fattyacids, and the like, are similarly usable. While any suitable polyvalentmetal soap may be used in accordance with the invention, the aluminumsoaps are preferred, and particularly aluminumstearate, palmitate orother saturated soaps of this'metal.

The invention will be further described in greater detail by thefollowing specific examples. It should be understood, however, thatalthough these examples may set forth in particular detail some of themore specific features of the invention, they are given primarily forpurposes of illustration of preferred preparations and evaluations andthe invention in its broader aspects is I not to be construed as limitedthereto.

Example 1 A soap solution was prepared from grams of 2-hydroxy-4-methyl-6,6-dimethyl heptanoic acid, 400 grams of Hydrofol 51(having the approximate composition: 7.5% C14; 33.3% C16; 27.2% C13;17.2% C20; 14.8% C22; 4.3% unsaturated acids); 'grarns of 98% sodiumhydroxide and 1500 grams of water. This solution was heated to atemperature of approximately 65 C. and a second solution comprising 270grams of alum and 2000 grams of water was added thereto. The aluminumsoap precipitate which formed was filtered, washed on a laboratory crockand dried overnight at a temperature of approximately 75 C. The driedmaterial was ground in a 3 inicropulverizer at a speed of approximately4000 R. P. M. through a V8 inch r. p. screen.

A 20% solution in commercial toluene was found to be very fluid at roomtemperature and could be easily sprayed on fabrics, paper, woodshingles, concrete and other building materials as a waterproofing agenttherefor.

A 20% solution in Stoddard solvent was very fluid and could be readilysprayed on textile materials, masonry, wall-board, asbestos, rockwool,and the like. The material was also readily soluble in benzene, xylene,carbon tetrachloride and similar aliphatic and aromatic hydrocarbons andtheir halogenated derivatives.

A laboratory analysis of the aluminum soap indicated the following:10.10% ash, 9.22% washed ash; 0.88% water-soluble ash; 5.9 mgm. KOH acidvalue (hot acetone extraction method).

Example 2 A soap solution was prepared from 200 grams of alpha hydroxydecanoic acid; 800 grams of Hydrofol 45 (1.5% C14; 28.0% C15; 70.5% Cm;6.0% unsaturated acids), 175 grams of 98% sodium hydroxide and 15,000grams of water. This solution was heated to a temperature ofapproximately 65 C. and a second solution comprising 400 grams of zincsulfate and 500 grams of water was added thereto. The zinc soapprecipitate which formed was filtered, washed on a laboratory c'i'ockand dried overnight at a temperature of approximately 75 C. The driedproduct was ground in a micro-pulverizer at 4000 R. P. M. through a $43inch r. p. screen. A laboratory analysis of the zinc soap indicated thefollowing:

16.65% ash, 14.7% washed ash and 1.9% water-solubles. A 15% solution incommercial toluene was applied as a waterproofing agent to woodshingles, concrete, cement, and similar building materials.

Example 3 A soap solution was prepared from 200 grams of alphahydroxydecanoic acid, 800 grams of Hydrofol 51, 212

grams of 98% sodium hydroxide and 15,000 grams of water. This solutionwas heated to a temperature of approximately 65 C. and a second solutioncomprising 540 grams of alum and 2500 grams of water was added thereto.The aluminum soap precipitate which formed was filtered, washed, anddried overnight in an oven maintained at a temperature of approximately75 C. A laboratory analysis of the aluminum soap indicated: 10.05% ash;9.18% washed ash; 0.87% water-soluble ash and 20.7 mgm. KOH acid value.A 30% solution in alpha-pinene was heated to 67 C. and was very thin andclear while hot. It was a readily sprayable waterproofing solution andcould be sprayed on various surfaces such as wood, masonry, and thelike. A solution in Stoddard solvent was fluid and could be easilysprayed. A solution in commercial toluene was similarly fluid and couldalso be readily sprayed. A solution in commercial toluene was slightlythicker but still fluid.

The solubility of the aluminum soap was investigated further as follows:It was found to be clear, thin and readily sprayable in 15 solutions ofpetroleum ether, carbon tetrachloride, trichlorobenzene, cyclohexane,and other similar solvents.

Example 4 A soap solution was prepared from 100 grams of alpha-hydroxydecanoic acid, 17 grams of 98% sodium hydroxide and 4000 grams of water.This solution was heated to a temperature of approximately C. and to itwas added a second solution comprising 45 grams of zinc sulfate and 2500grams of water. The zinc soap precipitate which formed was filtered,washed and dried overnight in an oven maintained at a temperature ofapproximately 75 C. A laboratory analysis of the zinc soap indicated thefollowing: 14.95% ash; 13.37% washed ash; 1.58% water-soluble ash; and1.6 mgm. KOH acid value.

A 15 solution in commercial toluene was heated to C., was very fluid andcould be readily sprayed as a waterproofing agent. On cooling, thesolution remained very thin and fluid and retained its sprayablecharacteristics.

Example 5 r The following materials were employed to prepare thealuminum soap of alpha-hydroxy decanoic acid and mixed fatty acids:

800 grams of Hydrofol 55 200 grams of alpha-hydroxy decanoic acid 212grams of 98% sodium hydroxide 540 grams of alum 18,500 grams of water.

Various methods of precipitation were used to form the aluminum soap. Inthe first method, the alum solution was added to the sodium soap. In thesecond method, the sodium soap solution was added to the alum solution;and in the third method; the sodium soap solution and the alum solutionwere added simultaneously to the precipitation tank.

All three methods were found to be satisfactory but the second methodwas found to produce a filter cake which was not too grainy and asmoother resulting product. The temperatures of precipitation werevaried from about 50 to about 80 and all temperatures were foundsatisfactory although it was noted that a lower temperature occasionallyprevented the formation of a precipitate which was too grainy.

Example 6 The procedures set forth in Example 1 were followedsubstantially as set forth therein with the exception that a singlepressed stearic acid was substituted for the mixed fatty acids usedtherein The resulting aluminum soap was very similar to that derivedfrom Example 1.

Example] A soap solution was prepared from 100 grams of alphahydroxycapric acid, 400 grams of Hydrofol 405, 100 grams of 98% sodiumhydroxide and 16,000 grams of water. This solution was heated to atemperature of approximately 65 C. and a second solution comprising 540grams of alum and 500 grams of water was added thereto. The aluminumsoap precipitate which formed was filtered and washed and then driedovernight at a temperature of about 70 C. A laboratory analysis of thedried material indicated the following: 9.13% ash; 8.8% washed ash;0.33% water-soluble ash; and 18.7 mgm. KOH acid value. A 10% solution incommercial toluene was used as a waterproofing agent and was sprayed oncotton, wool, asbestos, and like textile materials. A 15% solution incommercial toluene was applied to wood shingles, concrete, cement,masonry, and like building materials.

Example 8 A soap solution was prepared from 400 grams of Emersol 110 (amixture of C12 to C18 fatty acids), 100 grams of 2-ethyl-3-hydroxyhexanoic acid, 100 grams of 98% sodium hydroxide and 16,000 grams ofwater. This solution was heated to a temperature of approximately 75 C.and to it was added a second solution comprising 270 grams of alum and1000 grams of water. The aluminum soap which precipitated was filteredand Washed and then dried overnight in an oven at a temperature ofapproximately 80 C. Laboratory analysis indicated the following: 9.57%ash; 8.71% washed ash; 0.86% watersoluble ash; 2.26% moisture andvolatile matter at C. and 28.6 mgm. KOH acid value. 10% waterproofingsolutions in commercial toluene were applied to concrete, cement,masonry, and like building materials.

The quantity by weight of alpha-hydroxy alkanoic acids used inproportion to the total acid in the preparation of the soap may bevaried within wide As little as 1% or less by weight of thealpha-hydroxy acid may be used and as high as up to 100% may be used,although the higher cost of such compositions renders them commerciallyand economically impracticable as coating, impregnating, sealing, orwaterproofing agents. In general, it may be stated that compositionscontaining from about 5% to about 30% by weight of the alpha-hydroxyalkanoic acid, are economically and industrially most desirable.

As shown primarily in the examples, these metallic soaps are soluble upto as high as 30% in a very wide range of solvents without becoming toothick or gelatinous to use readily. It was observed that in many cases,aluminum stearate, when used without the addition of the alpha-hydroxyacid, could not form the thin and clear concentrated solutions whichwere sprayable, which solutions were made possible by the addition ofthe hydroxy acids during the soap formation.

This viscosity reducing characteristic created by the use of such anacid is also of value in decreasing the viscosity, when desired, ofother compounded compositions such as greases, waxes, soaps, paints,varnishes, plastics, cosmetics, adhesives, rubber and the like.

Although we have described several specific embodiments of our inventiveconcept, we consider the same not to be limited thereto nor to thespecific substances and compounds mentioned therein, but to includevarious other compounds and compositions of equivalent constitution asset forth in the claims appended hereto. It is understood, of course,that any suitable changes, modifications and variations may be madewithout departing from the spirit and scope of the invention.

What we claim is:

1. A soap composition comprising metal soaps of about 5% to 30% byweight of an alpha-hydroxy alkanoic acid containing from 8 to 12 carbonatoms and 95% to 70% by weight of a fatty acid containing from to 22carbon atoms, said metal being selected from the group consisting ofaluminum, zinc, calcium and magnesium.

2. A composition according to claim 1 wherein the alpha-hydroxy alkanoicacid is alpha-hydroxy decanoic acid.

3. A composition according to claim 1 wherein the alpha-hydroxy alkanoicacid is 2-hydroxy-3-ethyl heptanoic acid.

4. A soap composition comprising an aluminum soap of about 5% to 30% byweight of an alpha-hydroxy alkanoic acid containing from 8 to 12 carbonatoms and 95% to by weight of a fatty acid containing from 10 to 22carbon atoms.

5. A water-proofing composition comprising a volatile hydrocarbonsolvent containing up to 30% of a metal soap of about 5% to 30% byweight of an alpha-hydroxy alkanoic acid containing from 8 to 12 carbonatoms and to 70% by weight of a fatty acid containing from 10 to 22carbon atoms, said metal being selected from the group consisting ofaluminum, zinc, calcium and magnesium.

6. A water-proofing composition according to claim 5 wherein thealpha-hydroxy alkanoic acid is alpha-hydroxy decanoic acid.

7. A water-proofing composition according to claim 5 wherein thealpha-hydroxy alkanoic acid is Z-hydroxy- 3-ethyl-heptanoic acid.

References Cited in the file of this patent UNITED STATES PATENTS2,081,407 Minich May 25, 1937 2,223,158 Licata et a1. Nov. 26, 19402,350,688 Licata et a1. June 6, 1944 2,453,520 Lang Kammerer Nov. 9,1948 2,618,596 Minich et a1. Nov. 18, 1952 2,626,897 Young et a1. Jan.27, 1953 2,628,202 Allison et al. Feb. 10, 1953

1. A SOAP COMPOSITION COMPRISING METAL SOAPS OF ABOUT 5% TO 30% BYWEIGHT OF AN ALPHA-HYDROXY ALKANOIC ACID CONTAINING FROM 8 TO 12 CARBONATOMS AND 95% TO 70% BY WEIGHT OF A FATTY ACID CONTAINING FROM 10 TO 22CARBON ATOMS, SAID METAL BEING SELECTED FROM THE GROUP CONSISTING OFALUMINUM, ZINC, CALCIUM AND MAGNESIUM.